Question: $ { {-3} \times \left[\begin{array}{rr}{1} & {-2} \\ {-1} & {-1}\end{array}\right] = {?} } $
Explanation: To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rr}{-3}\times{1} & {-3}\times{-2} \\ {-3}\times{-1} & {-3}\times{-1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{-3} & {6} \\ {3} & {3}\end{array}\right]}$